cello vs kit violin

cello

noun
  • A large unfretted stringed instrument of the violin family with four strings tuned (lowest to highest) C-G-D-A and an endpin to support its weight, usually played with a bow. 

  • cellophane 

kit violin

noun
  • A very small long-necked violin that came in a variety of shapes and configurations, meant to be carried in a pocket and intended for dancing instructors to carry to accompany their students. 

How often have the words cello and kit violin occurred in a corpus of books? (source: Google Ngram Viewer )